[sdiy] Prophet modulation refresh rate (was NPO caps in P08 and Andromeda)

[Tom Wiltshire]

On 10 Dec 2008, at 19:33, Dave Manley wrote:

> I'm a little surprised someone hasn't modded an evolver and posted  
> some comparisons.  If it made a significant audio difference, you'd  
> think this would be a popular mod.
>
> With regard to the S/H caps - I believe they are being refreshed at  
> a high rate, so don't need big, high quality caps.

That's a question I'd love to know the answer to: what is the refresh  
rate of the modulations in the Prophet 08?

The reason I ask is that I spend a lot of time playing with the same  
dsPIC chips Dave Smith uses in the Prophet, and I'm using them for  
much the same thing (generating LFOs and envelopes and other mod  
sources for output to a DAC) so I'd love to know what sample rate he  
uses for his modulations. I suspect it's slower than I'd presently  
countenance, and that I should get over it and recognise that there's  
really no need for mods to go as fast as I think they need to! After  
all, I've never read a review or seen a blog entry complaining about  
slow envelopes or sluggish modulation on the new Prophet, although  
one or two mention that some parts of the analogue circuitry don't  
keep up with the highest LFO rates (260Hz).

T.